The seal arrangement has a seal element which is formed in a segmented and annular manner. In its intended state, the seal extends between the two turbine casings and engages in an annular receiving groove by means of at least one of its radial end regions. Furthermore, the invention relates to the use of such a seal arrangement for sealing an annular gap between a high-pressure steam space and an adjacent low-pressure steam space, to a turbine having at least two turbine casings, in each case split into two casing halves, which between them form a high-pressure steam space and a low-pressure steam space, wherein the steam spaces are separated from one another by an annular gap defined between the turbine casings, and to a method for repairing a worn seal arrangement of the abovementioned type.
In steam turbines, normally annular seal elements are used to seal annular gaps between two mutually adjacent steam spaces. The gaps are defined between two turbine casings in each case split into two casing halves. The seal elements normally have an I-shaped cross section and are split into two segments to enable them to be mounted. In the intended arranged state, the mutually opposite radial end regions of the annular seal elements engage in annular receiving grooves formed opposite one another on the turbine casings or on their respective casing halves. When the turbine is in operation, the seal elements and in particular the annular receiving grooves are subjected to wear phenomena due to steam erosion and due to mechanical loads. Repair of the seal elements is not economically possible. As a result, these elements have to be replaced. Reconditioning the annular receiving grooves involves considerable effort, with associated high costs. This effort is difficult to reduce since it is impossible to determine in advance, with any precision, the point at which repairs are going to be necessary. One known way of counteracting the wear due to erosion consists in selecting an appropriate material. However, this also involves very high costs.